Footer redesign; revised language to be more accessible & mention FPF

Resolves #4662

install_files/ansible-base/roles/build-securedrop-app-code-deb-pkg/files/usr.sbin.apache2

@@ -267,6 +267,7 @@
   /var/www/securedrop/static/i/font-awesome/white/guard.svg r,
   /var/www/securedrop/static/i/hand_with_fingerprint.png r,
   /var/www/securedrop/static/i/logo.png rw,
+  /var/www/securedrop/static/i/logo-footer.png r,
   /var/www/securedrop/static/i/no16-global.png r,
   /var/www/securedrop/static/i/no16.png r,
   /var/www/securedrop/static/i/securedrop.png r,

securedrop/sass/modules/_footer.sass

@@ -2,7 +2,21 @@
   footer
     clear: both
     text-align: center
-    border-top: 1px dashed $color_grey_xlight
     margin-top: 20px
     padding-top: 20px
+
+  footer #footer-powered-by
+    color: #000
+    margin-bottom: 0.5em
+
+  footer #footer-advisory
+    color: #3b3b3b
+    line-height: 2
+
+  footer #footer-fpf
+    line-height: 2
     color: $color_grey_medium
+
+  footer img#footer-logo
+    vertical-align: -45%
+    margin-right: 0.5em

securedrop/source_templates/base.html

@@ -41,9 +41,7 @@
       </div>
 
       {% block footer %}
-      <footer>
-        {{ gettext('Like all software, SecureDrop may contain security bugs. Use at your own risk.') }} <br>{{ gettext('Powered by') }} SecureDrop {{ version }}.
-      </footer>
+      {% include 'footer.html' %}
       {% endblock %}
     </div>
   </body>

securedrop/source_templates/footer.html

@@ -0,0 +1,11 @@
+<footer>
+  <div id="footer-powered-by">
+    <img id="footer-logo" src="{{url_for('static', filename='i/logo-footer.png') }}" width="26" height="30">{{ gettext('Powered by') }} <strong>SecureDrop {{ version }}</strong>.
+  </div>
+  <div id="footer-advisory">
+    {{ gettext('Please note: Sharing sensitive documents may put you at risk, even when using Tor and SecureDrop.') }}
+  </div>
+  <div id="footer-fpf">
+    {{ gettext('SecureDrop is free and open source software stewarded by Freedom of the Press Foundation.') }}
+  </div>
+</footer>

securedrop/source_templates/index.html

@@ -72,10 +72,7 @@ <h2 class="welcome-text">
             </div>
         </div>
       </div>
-
-      <footer>
-        {{ gettext('Like all software, SecureDrop may contain security bugs. Use at your own risk.') }}<br>{{ gettext('Powered by') }} SecureDrop {{ version }}.
-      </footer>
+      {% include 'footer.html' %}
     </div>
 
     {# Warning bubble to help TB users disable JavaScript with NoScript.